| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| PEPA7 | Penstemon pallidus Small | pale beardtongue | Scrophulariaceae
|
| PEPAE | Penstemon palmeri Gray ssp. eglandulosus Keck | Penstemon palmeri var. eglandulosus | Scrophulariaceae
|
| PEPAT | Penstemon palmeri Gray ssp. typicus Keck | Penstemon palmeri var. palmeri | Scrophulariaceae
|
| PEPAE2 | Penstemon palmeri Gray var. eglandulosus (Keck) N. Holmgren | scented beardtongue | Scrophulariaceae
|
| PEPAM3 | Penstemon palmeri Gray var. macranthus (Eastw.) N. Holmgren | scented beardtongue | Scrophulariaceae
|
| PEPAP9 | Penstemon palmeri Gray var. palmeri | Palmer's penstemon | Scrophulariaceae
|
| PEPA8 | Penstemon palmeri Gray | Palmer's penstemon | Scrophulariaceae
|
| PEPA9 | Penstemon papillatus J.T. Howell | Inyo beardtongue | Scrophulariaceae
|
| PEPA10 | Penstemon �parishii Gray (pro sp.) | | Scrophulariaceae
|
| PEPA24 | Penstemon parryi (Gray) Gray | Parry's beardtongue | Scrophulariaceae
|
| PEPA25 | Penstemon parviflorus Pennell | Montezuma County beardtongue | Scrophulariaceae
|
| PEPA11 | Penstemon parvulus (Gray) Krautter | Penstemon azureus ssp. azureus | Scrophulariaceae
|
| PEPA26 | Penstemon parvus Pennell | Aquarius Plateau beardtongue | Scrophulariaceae
|
| PEPA27 | Penstemon patens (M.E. Jones) N. Holmgren | Lone Pine beardtongue | Scrophulariaceae
|
| PEPA28 | Penstemon patricus N. Holmgren | Penstemon leonardii var. patricus | Scrophulariaceae
|
| PEPA47 | Penstemon pauciflorus auct. non Greene | Penstemon ramosus | Scrophulariaceae
|
| PEPA29 | Penstemon payettensis A. Nels. & J.F. Macbr. | Payette beardtongue | Scrophulariaceae
|
| PEPA30 | Penstemon paysoniorum Keck | Payson's beardtongue | Scrophulariaceae
|
| PEPE10 | Penstemon peckii Pennell | Peck's beardtongue | Scrophulariaceae
|
| PEPE32 | Penstemon �peirsonii Munz & I.M. Johnston (pro sp.) | | Scrophulariaceae
|
| PEPE25 | Penstemon penlandii W.A. Weber | Penland's beardtongue | Scrophulariaceae
|
| PEPE11 | Penstemon pennellianus Keck | Blue Mountain beardtongue | Scrophulariaceae
|
| PEPE17 | Penstemon penstemon (L.) Britt. | Penstemon laevigatus | Scrophulariaceae
|
| PEPE12 | Penstemon perpulcher A. Nels. | Minidoka beardtongue | Scrophulariaceae
|
| PEPE3 | Penstemon personatus Keck | closethroat beardtongue | Scrophulariaceae
|
| PEPE13 | Penstemon petiolatus Brandeg. | petiolate beardtongue | Scrophulariaceae
|
| PEPI3 | Penstemon pinifolius Greene | pineneedle beardtongue | Scrophulariaceae
|
| PEPI4 | Penstemon pinorum L.& J. Shultz | Pine Valley penstemon | Scrophulariaceae
|
| PEPL4 | Penstemon platyphyllus Rydb. | broadleaf beardtongue | Scrophulariaceae
|
| PEPR6 | Penstemon pratensis Greene | western whiteflower beardtongue | Scrophulariaceae
|
| PEPRA | Penstemon procerus Dougl. ex Graham ssp. aberrans (M.E. Jones) Keck | Penstemon procerus var. aberrans | Scrophulariaceae
|
| PEPRB | Penstemon procerus Dougl. ex Graham ssp. brachyanthus (Pennell) Keck | Penstemon procerus var. brachyanthus | Scrophulariaceae
|
| PEPRF | Penstemon procerus Dougl. ex Graham ssp. formosus (A. Nels.) Keck | Penstemon procerus var. formosus | Scrophulariaceae
|
| PEPRM | Penstemon procerus Dougl. ex Graham ssp. modestus (Greene) Keck | Penstemon procerus var. modestus | Scrophulariaceae
|
| PEPRA2 | Penstemon procerus Dougl. ex Graham var. aberrans (M.E. Jones) A. Nels. | pincushion beardtongue | Scrophulariaceae
|
| PEPRB2 | Penstemon procerus Dougl. ex Graham var. brachyanthus (Pennell) Cronq. | pincushion beardtongue | Scrophulariaceae
|
| PEPRF2 | Penstemon procerus Dougl. ex Graham var. formosus (A. Nels.) Cronq. | pincushion beardtongue | Scrophulariaceae
|
| PEPRM2 | Penstemon procerus Dougl. ex Graham var. modestus (Greene) N. Holmgren | pincushion beardtongue | Scrophulariaceae
|
| PEPRP | Penstemon procerus Dougl. ex Graham var. procerus | pincushion beardtongue | Scrophulariaceae
|
| PEPRT | Penstemon procerus Dougl. ex Graham var. tolmiei (Hook.) Cronq. | Tolmie's penstemon | Scrophulariaceae
|
| PEPR2 | Penstemon procerus Dougl. ex Graham | littleflower penstemon | Scrophulariaceae
|
| PEPR3 | Penstemon pruinosus Dougl. ex Lindl. | Chilean beardtongue | Scrophulariaceae
|
| PEPS4 | Penstemon pseudoparvus Crosswhite | Mt. Washington beardtongue | Scrophulariaceae
|
| PEPS3 | Penstemon pseudoputus (Crosswhite) N. Holmgren | Kaibab Plateau beardtongue | Scrophulariaceae
|
| PEPSC | Penstemon pseudospectabilis M.E. Jones ssp. connatifolius (A. Nels.) Keck | desert beardtongue | Scrophulariaceae
|
| PEPSP | Penstemon pseudospectabilis M.E. Jones ssp. pseudospectabilis | desert beardtongue | Scrophulariaceae
|
| PEPST | Penstemon pseudospectabilis M.E. Jones ssp. typicus Keck | Penstemon pseudospectabilis ssp. pseudospectabilis | Scrophulariaceae
|
| PEPS | Penstemon pseudospectabilis M.E. Jones | desert penstemon | Scrophulariaceae
|
| PEPU14 | Penstemon puberulentus Rydb. | Penstemon gairdneri var. oreganus | Scrophulariaceae
|
| PEPU11 | Penstemon pudicus Reveal & Beatley | Kawich Range beardtongue | Scrophulariaceae
|
| PEPU17 | Penstemon pulchellus Lindl. | Penstemon campanulatus | Scrophulariaceae
|
| PEPU12 | Penstemon pumilus Nutt. | Salmon River beardtongue | Scrophulariaceae
|
| PEPU4 | Penstemon purpusii Brandeg. | Snow Mountain beardtongue | Scrophulariaceae
|
| PEPU13 | Penstemon putus A. Nels. | Black River beardtongue | Scrophulariaceae
|
| PERA2 | Penstemon radicosus A. Nels. | matroot penstemon | Scrophulariaceae
|
| PERA8 | Penstemon ramosus Crosswhite | lanceleaf beardtongue | Scrophulariaceae
|
| PERAK | Penstemon rattanii Gray ssp. kleei (Greene) Keck | Santa Cruz Mountains beardtongue | Scrophulariaceae
|
| PERAR2 | Penstemon rattanii Gray ssp. rattanii | Rattan's beardtongue | Scrophulariaceae
|
| PERAK2 | Penstemon rattanii Gray var. kleei (Green) Gray | Penstemon rattanii ssp. kleei | Scrophulariaceae
|
| PERAM | Penstemon rattanii Gray var. minor Gray | Penstemon anguineus | Scrophulariaceae
|
| PERA3 | Penstemon rattanii Gray | Rattan's beardtongue | Scrophulariaceae
|
| PERE7 | Penstemon retrorsus Payson ex Pennell | Adobe Hills beardtongue | Scrophulariaceae
|
| PERH6 | Penstemon rhizomatosus N. Holmgren | | Scrophulariaceae
|
| PERIC2 | Penstemon richardsonii Dougl. ex Lindl. ssp. curtiflorus Keck | Penstemon richardsonii var. curtiflorus | Scrophulariaceae
|
| PERID2 | Penstemon richardsonii Dougl. ex Lindl. ssp. dentatus Keck | Penstemon richardsonii var. dentatus | Scrophulariaceae
|
| PERIC3 | Penstemon richardsonii Dougl. ex Lindl. var. curtiflorus (Keck) Cronq. | cutleaf beardtongue | Scrophulariaceae
|
| PERID3 | Penstemon richardsonii Dougl. ex Lindl. var. dentatus (Keck) Cronq. | cutleaf beardtongue | Scrophulariaceae
|
| PERIR | Penstemon richardsonii Dougl. ex Lindl. var. richardsonii | Richardson's penstemon | Scrophulariaceae
|
| PERI | Penstemon richardsonii Dougl. ex Lindl. | cutleaf beardtongue | Scrophulariaceae
|
| PERO12 | Penstemon roezlii Regel | Roezl's penstemon | Scrophulariaceae
|
| PERO10 | Penstemon rostriflorus Kellogg | Bridge penstemon | Scrophulariaceae
|
| PEROJ | Penstemon rothrockii Gray ssp. jacintensis (Abrams) Keck | Keckiella rothrockii ssp. jacintensis | Scrophulariaceae
|
| PERO8 | Penstemon rothrockii Gray | Keckiella rothrockii ssp. rothrockii | Scrophulariaceae
|
| PERU5 | Penstemon rubicundus Keck | Wassuk Range beardtongue | Scrophulariaceae
|
| PERU | Penstemon rupicola (Piper) T.J. Howell | cliff beardtongue | Scrophulariaceae
|
| PERYA2 | Penstemon rydbergii A. Nels. ssp. aggregatus (Pennell) Keck | Penstemon rydbergii var. aggregatus | Scrophulariaceae
|
| PERYA | Penstemon rydbergii A. Nels. var. aggregatus (Pennell) N. Holmgren | meadow beardtongue | Scrophulariaceae
|
| PERYO | Penstemon rydbergii A. Nels. var. oreocharis (Greene) N. Holmgren | herbaceous penstemon | Scrophulariaceae
|
| PERYR | Penstemon rydbergii A. Nels. var. rydbergii | swollen penstemon | Scrophulariaceae
|
| PERYV | Penstemon rydbergii A. Nels. var. varians (A. Nels.) Cronq. | Penstemon rydbergii var. rydbergii | Scrophulariaceae
|
| PERY | Penstemon rydbergii A. Nels. | Rydberg's penstemon | Scrophulariaceae
|
| PESA2 | Penstemon saxosorum Pennell | upland beardtongue | Scrophulariaceae
|
| PESC2 | Penstemon scapoides Keck | pinyon beardtongue | Scrophulariaceae
|
| PESCA | Penstemon scariosus Pennell var. albifluvis (England) N. Holmgren | White River beardtongue | Scrophulariaceae
|
| PESCC | Penstemon scariosus Pennell var. cyanomontanus Neese | Neese's Blue Mountain beardtongue | Scrophulariaceae
|
| PESCG | Penstemon scariosus Pennell var. garrettii (Pennell) N. Holmgren | Garrett's beardtongue | Scrophulariaceae
|
| PESCS | Penstemon scariosus Pennell var. scariosus | White River beardtongue | Scrophulariaceae
|
| PESC5 | Penstemon scariosus Pennell | White River beardtongue | Scrophulariaceae
|
| PESE11 | Penstemon secundiflorus Benth. | sidebells penstemon | Scrophulariaceae
|
| PESE12 | Penstemon seorsus (A. Nels.) Keck | shortlobe penstemon | Scrophulariaceae
|
| PESE13 | Penstemon sepalulus A. Nels. | littlecup beardtongue | Scrophulariaceae
|
| PESE5 | Penstemon serrulatus Menzies ex Sm. | serrulate penstemon | Scrophulariaceae
|
| PESH | Penstemon shastensis Keck | Penstemon heterodoxus var. shastensis | Scrophulariaceae
|
| PESM | Penstemon smallii Heller | Small's beardtongue | Scrophulariaceae
|
| PESP2 | Penstemon spatulatus Pennell | Wallowa beardtongue | Scrophulariaceae
|
| PESPK | Penstemon speciosus Dougl. ex Lindl. ssp. kennedyi (A. Nels.) Keck | Penstemon speciosus | Scrophulariaceae
|
| PESPL | Penstemon speciosus Dougl. ex Lindl. ssp. lemhiensis Keck | Penstemon lemhiensis | Scrophulariaceae
|
| PESP | Penstemon speciosus Dougl. ex Lindl. | royal penstemon | Scrophulariaceae
|
| PESPS2 | Penstemon spectabilis Thurb. ex Gray ssp. spectabilis | showy penstemon | Scrophulariaceae
|
| PESPS | Penstemon spectabilis Thurb. ex Gray ssp. subviscosus Keck | showy penstemon | Scrophulariaceae
|
| PESPS3 | Penstemon spectabilis Thurb. ex Gray var. subviscosus (Keck) McMinn | Penstemon spectabilis ssp. subviscosus | Scrophulariaceae
|